Poststroke QEEG informs early prognostication of cognitive impairment

Abstract

Cognitive impairment is a common consequence of stroke, but remains difficult to predict. We investigate the ability of early QEEG assessment to inform such prediction, using binary logistic regression. Thirty-five patients (12 female, ages 18-87) suffering middle cerebral artery, ischemic stroke were studied. Resting-state EEG was recorded 48-239 h after symptom onset. Relative power for delta, theta, alpha, and beta bands, delta:alpha ratio, and peak alpha frequency were analyzed. Montreal Cognitive Assessment (MoCA) was administered, where possible, on day of EEG and at median 99 days (range 69-138) poststroke. Eight patients could not complete the baseline MoCA, and four the follow-up MoCA, for varying reasons (most commonly, stroke symptoms). Fifteen patients (48%) had cognitive impairment (MoCA score ≤25) at follow-up. One QEEG index was able to correctly predict presence/absence of cognitive impairment in 24/31 patients (77.4%), whereas predischarge MoCA did so in 23 patients. This index, relative theta frequency (4-7.5 Hz) power, was computed from only three posterior electrodes over the stroke-affected hemisphere. Its predictive accuracy (three electrodes) was higher than that of any "global" QEEG measure (averaged over 19 electrodes). These results may signify association between poststroke alpha slowing and cognitive impairment, which may be mediated by attentional (dys)function, which warrants further investigation. Pending further studies, QEEG measure(s)-from a few electrodes-could inform early prognostication of poststroke cognitive outcomes (and clinical decisions), particularly when cognitive function cannot be adequately assessed (due to symptoms, language, or other issues) or when assessment is equivocal.

Slower EEG alpha generation, synchronization and “flow”—possible biomarkers of cognitive impairment and neuropathology of minor stroke

“…In addition, many studies demonstrated that some qEEG indices are also sensitive to cognitive function ( Klimesch, 2012 ) and mild cognitive impairment or dementia ( Dubovik et al, 2013 ; Schleiger et al, 2014 ; Schleiger et al, 2017 ; Song et al, 2015 ). In line with the general view regarding cognitive and memory performance ( Klimesch, 1999 ), these studies indicated that the alpha, as well as theta frequency, could be of interest for the screening of post-stroke cognitive impairment ( Dubovik et al, 2013 ; Schleiger et al, 2014 ; Schleiger et al, 2017 ; Song et al, 2015 ).…”

“…In addition, many studies demonstrated that some qEEG indices are also sensitive to cognitive function ( Klimesch, 2012 ) and mild cognitive impairment or dementia ( Dubovik et al, 2013 ; Schleiger et al, 2014 ; Schleiger et al, 2017 ; Song et al, 2015 ). In line with the general view regarding cognitive and memory performance ( Klimesch, 1999 ), these studies indicated that the alpha, as well as theta frequency, could be of interest for the screening of post-stroke cognitive impairment ( Dubovik et al, 2013 ; Schleiger et al, 2014 ; Schleiger et al, 2017 ; Song et al, 2015 ). In contrast to relative theta power, whether global, as demonstrated by Song et al (2015) , or posterior, computed from three electrodes, as shown in Schleiger et al (2017) , the qEEG assessments revealed global alpha power ( Schleiger et al, 2014 ), EEG alpha band synchrony ( Dubovik et al, 2013 ), as well as a lower peak alpha frequency ( Schleiger et al, 2017 ) to be informative as regards post-stroke cognitive impairment.…”

Quantitative and Qualitative EEG as a Prediction Tool for Outcome and Complications in Acute Stroke Patients

“…42 In another study by the same working group, relative theta power in the posterior region ipsilateral to the stroke was an independent predictor of cognitive impairment after 3 months. 43 Aminov et al 44 used a single dry electrode (FP1) to investigate 19 acute stroke patients and correlated absolute power and power indices from this electrode to MoCA results at day 90 after stroke. Higher relative power of theta was associated with better cognitive outcome, while greater values of delta, deltatheta ratio (DTR), and DAR were associated with poor cognitive outcome.…”

Peer Review #1 of "Slower EEG alpha generation, synchronization and “flow”—possible biomarkers of cognitive impairment and neuropathology of minor stroke (v0.1)"

“…In addition, many studies demonstrated that some qEEG indices are also sensitive to cognitive function (Klimesh, 2012) and to mild cognitive impairment or dementia (Dubovik et al, 2013;Schleiger et al, 2014Schleiger et al, , 2017Song et al, 2015). In line with the general view regarding cognitive and memory performance (Klimesch, 1999), these studies indicated that the alpha, as well as theta frequency, could be of interest for the screening of post-stroke cognitive impairment (Dubovik et al, 2013;Schleiger et al, 2014Schleiger et al, , 2017Song et al, 2015).…”

“…In addition, many studies demonstrated that some qEEG indices are also sensitive to cognitive function (Klimesh, 2012) and to mild cognitive impairment or dementia (Dubovik et al, 2013;Schleiger et al, 2014Schleiger et al, , 2017Song et al, 2015). In line with the general view regarding cognitive and memory performance (Klimesch, 1999), these studies indicated that the alpha, as well as theta frequency, could be of interest for the screening of post-stroke cognitive impairment (Dubovik et al, 2013;Schleiger et al, 2014Schleiger et al, , 2017Song et al, 2015). In contrast to relative theta power, whether global, as demonstrated by Song et al (2015), or posterior, computed from three electrodes, as shown in Schleiger et al (2017), the qEEG assessments revealed global alpha power (Schleiger et al, 2014), EEG alpha band synchrony (Dubovik et al, 2013), as well as a lower peak alpha frequency (Schleiger et al, 2017) to be informative as regards post-stroke cognitive impairment.…”